Lipid metabolism in fish (Trichogaster), in particular conversions of fatty acids, fatty alcohols and wax esters will be studied on the subcellular level. The enzymatic reactions will be characterized for different tissues of the mature fish, the eggs and the fry. Nutritional studies will imply mainly the metabolism of polyunsaturated lipids to characterize their essentiality for the fish and the fry. Incorporation and clearing of toxic chemicals in fish will be studied with reference to lipid turnover and it will be attempted to influence their elimination in conjunction with the turnover of lipids.